Problems in sulfur recovery units
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The sulfur recovery unit designed today is equipped with an on-line detector on the gas phase of the condenser at the outlet of the Claus reactor; this detector is interlocked with the air control valve at the inlet of the acidic gas combustion furnace, in order to control and measure the H2S:SO2 ratio at 2:1. The purpose is to maintain this 2:1 ratio of H2S:SO2 as it enters the Claus reactor. But why is this detector installed on the exhaust gas pipeline rather than on the process pipeline at the inlet of the Claus reactor?
In the Claus reaction, the sulfur conversion rate is highest when the ratio of hydrogen sulfide to sulfur dioxide is 2 to 1. This ratio is ensured through an appropriate air supply volume to the combustion furnace; however, if the air supply volume is not suitable (too much or too little), the ratio of hydrogen sulfide to sulfur dioxide entering the reactor will deviate from 2. The reaction between the two to produce sulfur and water in the reactor is reversible; if their ratio is not 2, after passing through two-stage or three-stage reactors, the ratio between them in the process gas will deviate from 2 even more than it did before entering the reactor. (Assuming it is 1.9 or 2.1 before entering the reactor, the corresponding ratio after reaction may be 1.6 or 2.5.) Therefore, online analysis is employed after the reactor in order to more accurately determine whether the air supply volume is appropriate; if the analyzed ratio is 2.1, it indicates that the ratio before entering the reactor is a value less than 2.1 but slightly greater than 2. Doing this serves to amplify the deviation, thereby enabling more precise control of the air volume entering the furnace.
The explanation on the second floor was quite insightful; it was educational, great!
Thank you to the friend in floor 2 for their answer; it was very helpful!!!! This post was last edited by mlh517 on 2007-12-6 08:13.]
What was said on the second floor is correct: as much of it as can be converted is converted into liquid sulfur for recovery (the ratio of hydrogen sulfide to sulfur dioxide that gets converted is definitely 2:1). The ratio of remaining hydrogen sulfide to sulfur dioxide in the exhaust gas is measured in order to fine-tune the air supply to the combustion furnace, which essentially means amplifying any deviations. Controlling the air supply volume at 20% or 30% based on the analysis results from this ratio analyzer is also considered a classic control method in sulfur production
What was said on the 2nd floor is relatively correct; however, during operation, due to the highly complex composition of the sulfur recovery exhaust gases, the analyzers often provide inaccurate readings, making it difficult to achieve a 2:1 ratio in practical applications. Generally, exhaust gas detectors for sulfur recovery are imported devices, and the level of localization is relatively low.
I’ve learned it. What was said on the 2nd floor is right
I’m currently reviewing TECHNIP’s SRU unit design; I’m very grateful for the explanations provided by the person on the 2nd floor
As we move further forward, the concentration of sulfur vapor in the gas phase decreases, the dew point drops, and the likelihood of sulfur clogging occurring in the analyzer becomes smaller. . . This is another reason. The device using MCRC in the Sichuan gas field features a ratio analyzer at the primary outlet, where sulfur blockages occur frequently, causing a lot of problems. . .
I’ve learned a lot! Thank you so much to the Haiyou on the second floor!
Thank you all. I’m considering the analyzer option, and what you said has been very helpful to me
I am working on WSA sulfur recovery